Stereo camera and height acquisition method thereof and height acquisition system

ABSTRACT

Disclosed are systems and methods for acquiring height of a stereo camera, applied to the stereo camera. An example method includes acquiring angle information of a stereo camera, with the angle information including a pitch angle and a tilt angle. A ground image of a scenario where the stereo camera is deployed is captured and depth information of each pixel on the ground image is determined. A three-dimensional point set based on depth information of each pixel on the ground image is established, with the three-dimensional point set including coordinate information of each three-dimensional point corresponding to each pixel of the ground image. Height of the stereo camera is determined based on the angle information and the three-dimensional point set.

This application claims priority to, and is a continuation of,PCT/CN2018/076571, filed on Feb. 12, 2018, which claims the benefit ofpriority to Chinese Application No. 201710100940.1, filed on Feb. 23,2017 and entitled “STEREO CAMERA AND HEIGHT ACQUISITION METHOD.” Each ofthe above recited applications is hereby incorporated herein byreference in its entirety. Any and all applications for which a foreignor domestic priority claim is identified in the Application Data Sheetas filed with the present application are hereby incorporated byreference under 37 CFR 1.57 for all purposes and for all that theycontain.

TECHNICAL FIELD

The present disclosure relates to the field of application of electronictechnology, and particularly to a stereo camera, and height acquisitionmethod and height acquisition system thereof.

BACKGROUND

Stereo cameras are cameras for reconstructing three-dimensionalgeometric information of a scenario. The stereo camera includes, but notlimited to, a binocular stereo camera, a time of flight (TOF) stereocamera or the like which is capable of acquiring the three-dimensionalinformation.

SUMMARY

Examples of the present disclosure provide a stereo camera, and a heightacquisition method and system thereof.

According to a first aspect of the present disclosure, there is provideda method for acquiring a height of a stereo camera, applied to thestereo camera, the method comprising:

acquiring angle information of a stereo camera, wherein the angleinformation includes a pitch angle and a tilt angle;

capturing a ground image of a scenario where the stereo vision camera isdeployed;

determining depth information of each pixel on the ground image;

establishing a three-dimensional point set based on the depthinformation of each pixel on the ground image, wherein thethree-dimensional point set includes coordinate information of eachthree-dimensional point corresponding to each pixel of the ground image;and

determining the height of the stereo camera based on the angleinformation and the three-dimensional point set.

Optionally, wherein the determining height of the stereo camera based onthe angle information and the three-dimensional point set, comprises:

determining, based on the pitch angle and the tilt angle, a referenceplane equation corresponding to a reference plane, wherein the referenceplane is parallel to a horizon plane in a world coordinate system, and acenter point of a lens of the stereo camera is within the referenceplane;

calculating distances between each three-dimensional point in thethree-dimensional point set and the reference plane to obtain a distanceset; and

determining the height of the stereo camera based on the distances inthe distance set.

Optionally, wherein the determining, based on the pitch angle and thetilt angle, a reference plane equation corresponding to a referenceplane, comprises:

determining the reference plane equation ax+by+cz=0 based on the pitchangle θ and the tilt angle φ, such that a point (a, b, c) in a cameracoordinate system meets an angle conversion equation:

${{\lbrack y\rbrack = {\left\lbrack T^{- 1} \right\rbrack \lbrack x\rbrack}};{{{wherein}\mspace{14mu}\lbrack x\rbrack} = \begin{bmatrix}x_{r} \\y_{r} \\z_{r}\end{bmatrix}}},{\lbrack y\rbrack = \begin{bmatrix}x_{c} \\y_{c} \\z_{c}\end{bmatrix}},{\lbrack T\rbrack = \begin{bmatrix}{\cos \; \phi} & {\cos \; \theta \; \sin \; \phi} & {{- \sin}\; \theta \; \sin \; \phi} \\{{- \sin}\; \phi} & {\cos \; {\theta cos}\; \phi} & {{- \sin}\; {\theta cos}\; \phi} \\0 & {\sin \; \theta} & {\cos \; \theta}\end{bmatrix}},$

[T⁻¹] is an inverse of matrix [T], (x_(c), y_(c), z_(c)) is a point inthe camera coordinate system, and (x_(y), y_(y), z_(y)) is a point inthe world coordinate system corresponding to the point (x_(c), y_(c),z_(c)) in the camera coordinate system, wherein an origin of the worldcoordinate system coincides with an origin of the camera coordinatesystem, and coordinate axes of the world coordinate system arecorrespondingly parallel to coordinate axes of the world coordinatesystem.

Optionally, wherein the calculating distances between eachthree-dimensional point in the three-dimensional point set and thereference plane to obtain a distance set, comprises:

calculating a distance H_(i) between an i^(th) three-dimensional point(x_(i), y_(i), z_(i)) and the reference plane by using a first distancecalculation equation based on the three-dimensional point set and thereference plane equation, wherein the distance set comprises thedistance H_(i), 1≤i≤n, n being the total number of three-dimensionalpoints in the three-dimensional point set, and the first distancecalculation equation is:

${H_{i} = \frac{{{ax}_{i} + {by}_{i} + {cz}_{i}}}{\sqrt{a^{2} + b^{2} + c^{2}}}};$

wherein the reference plane equation is ax+by+cz=0, a, b and c beingcoefficients of ax+by+cz=0.

Optionally, wherein the determining the height of the stereo camerabased on the distances in the distance set, comprises:

combining the distances in the distance set to obtain a target distanceset, wherein value of distances in the target distance set are differentfrom each other, each distance has a number of times, and the timescount value indicates a times count of occurrences of a correspondingdistance in the distance set; and

determining a distance corresponding a maximum number of times in thetarget distance set as the height of the stereo camera.

Optionally, wherein the reference plane equation is ax+by+cz=0, a, b andc being coefficients of ax+by+cz=0; and

wherein the determining the height of the stereo camera based on thedistances in the distance set, comprises:

forming, by a predefined width as a class width, a distance histogramaccording the distance set, wherein herein a width in a horizontal axisof each rectangular column in the distance histogram indicates adistance range, and a length in a vertical axis of each rectangularcolumn in the distance histogram indicates the number of distanceswithin the distance range;

determining a middle point of width in the horizontal axis of arectangular column having a maximum distance range in the distancehistogram as a pre-selected height value H;

traversing, by a predefined step, each adjacent height value h aroundthe pre-selected height value H to obtain a set of pre-selected plane,wherein each pre-selected plane in the set of pre-selected plane meetsthe equation ax+by+cz+d=0, d=−h; and each adjacent height value h meetshϵ(h−σ, h+σ), σ being a predefined value, and σ being greater than orequal to the predefined step, and less than the predefined width;

calculating distances between each three-dimensional point and eachpre-selected plane based on the three-dimensional point set and the setof pre-selected plane;

determining a three-dimensional point with the distance to thepre-selected plane being greater than a predefined support threshold asa support point of the pre-selected plane;

determining a pre-selected plane having the most support points in thepre-selected planes set as a target plane; and

determining an average value of distances between each support point inthe target plane and the reference plane as the height of the stereocamera.

Optionally, wherein the calculating distances between eachthree-dimensional point and each pre-selected plane based on thethree-dimensional point set and the set of pre-selected plane,comprises:

calculating a distance Hi′ between the i^(th) three-dimensional point(x_(i), y_(i), z_(i)) and the first pre-selected plane by a seconddistance calculation equation based on the three-dimensional point setand the set of pre-selected plane, wherein 1≤i≤n, n being the totalnumber of three-dimensional points in the three-dimensional point set,and the second distance calculation equation being:

$H_{i} = \frac{{{ax}_{i} + {by}_{i} + {cz}_{i} + d}}{\sqrt{a^{2} + b^{2} + c^{2}}}$

wherein the first pre-selected plane is a pre-selected plane in the setof pre-selected plane.

Optionally, wherein the ground image includes a plurality of contiguousground images captured by the stereo camera; and

wherein the determining depth information of each pixel on the groundimage, comprises:

performing median filtering in time domain on the plurality ofcontiguous ground images to obtain a plurality of ground images aftermedian filtering in time domain;

performing median filtering in space domain on the plurality of groundimages after median filtering in time domain to obtain a plurality ofground images after median filtering in space domain; and

determining depth information of each pixel on the ground images aftermedian filtering in space domain.

Optionally, wherein the acquiring angle information of the stereo cameracomprises:

acquiring the angle information of the stereo camera by an angle sensorin the stereo camera.

According to a second aspect of the present disclosure, there isprovided a stereo camera, comprising:

an acquiring module, configured to angle information of a stereo camera,wherein the angle information includes a pitch angle and a tilt angle;

a capturing module, configured to capture a ground image of a scenariowhere the stereo camera is deployed;

a first determining module, configured to determine depth information ofeach pixel on the ground image;

an establishing module, configured to establish a three-dimensionalpoint set based on the depth information of each pixel on the groundimage, wherein the three-dimensional point set includes coordinateinformation of each three-dimensional point corresponding to each pixelof the ground image; and

a second determining module, configured to determine the height of thestereo camera based on the angle information and the three-dimensionalpoint set.

Optionally, wherein the second determining module comprises:

a first determining sub-module, configured to determine, based on thepitch angle and the tilt angle, a reference plane equation correspondingto a reference plane, wherein the reference plane is parallel to ahorizon plane in a world coordinate system, and a center point of a lensof the stereo camera is within the reference plane;

a calculating sub-module, configured to calculate distances between eachthree-dimensional point in the three-dimensional point set and thereference plane to obtain a distance set; and

a second determining module, configured to determine the height of thestereo camera based on the distances in the distance set.

Optionally, wherein the first determining sub-module is furtherconfigured to:

determine the reference plane equation ax+by+cz=0 based on the pitchangle θ and the tilt angle φ, such that a point (a, b, c) in a cameracoordinate system meets an angle conversion equation:

$\lbrack y\rbrack = {{\left\lbrack T^{- 1} \right\rbrack \lbrack x\rbrack}\mspace{14mu} {wherein}\mspace{11mu} {\quad\; {{\lbrack x\rbrack = \begin{bmatrix}x_{r} \\y_{r} \\z_{r}\end{bmatrix}},{\lbrack y\rbrack = \left\lbrack \begin{matrix}x_{c} \\y_{c} \\z_{c}\end{matrix} \right\rbrack},{\lbrack T\rbrack = \left\lbrack \begin{matrix}{\cos \; \phi} & {\cos \; \theta \; \sin \; \phi} & {{- \sin}\; \theta \; \sin \; \phi} \\{{- \sin}\; \phi} & {\cos \; {\theta cos}\; \phi} & {{- \sin}\; {\theta cos}\; \phi} \\0 & {\sin \; \theta} & {\cos \; \theta}\end{matrix} \right\rbrack},}}}$

[T⁻¹] is an inverse of matrix [T], (x_(c), y_(c), z_(c)) is a point inthe camera coordinate system, and (x_(y), y_(y), z_(y)) is a point inthe world coordinate system corresponding to the point (x_(c), y_(c),z_(c)) in the camera coordinate system, wherein an origin of the worldcoordinate system coincides with an origin of the camera coordinatesystem, and coordinate axes of the world coordinate system arecorrespondingly parallel to coordinate axes of the world coordinatesystem.

Optionally, wherein the calculating sub-module is further configured to:

calculate a distance H_(i) between an i^(th) three-dimensional point(x_(i), y_(i), z_(i)) and the reference plane by using a first distancecalculation equation based on the three-dimensional point set and thereference plane equation, wherein the distance set comprises thedistance H_(i), 1≤i·n, n being the total number of three-dimensionalpoints in the three-dimensional point set, and the first distancecalculation equation is:

${H_{i} = \frac{{{ax}_{i} + {by}_{i} + {cz}_{i}}}{\sqrt{a^{2} + b^{2} + c^{2}}}};$

wherein the reference plane equation is ax+by+cz=0, wherein a, b and cbeing coefficients of ax+by+cz=0.

Optionally, wherein the second determining sub-module is furtherconfigured to:

combine the distances in the distance set to obtain a target distanceset, wherein distances in the target distance set are different fromeach other, each distance corresponds a number of times, and the numberof times indicates a times count of occurrences of a correspondingdistance in the distance set; and

determine a distance corresponding a maximum number of times in thetarget distance set as the height of the stereo camera.

Optionally, wherein the reference plane equation is ax+by+cz=0, a, b andc being coefficients of ax+by+cz=0;

the second determining sub-module comprises:

a histogram establishing sub-module, configured to form, by a predefinedwidth as a class width, a distance histogram according the distance set,wherein herein a width in a horizontal axis of each rectangular columnin the distance histogram indicates a distance range, and a length in avertical axis of each rectangular column in the distance histogramindicates the number of distances within the distance range;

a pre-selected value determining sub-module, configured to determine amiddle point of width in the horizontal axis of a rectangular columncorresponding to a maximum distance range in the distance histogram as apre-selected height value H;

a set determining sub-module, configured to traverse, by a predefinedstep, each adjacent height value h around the pre-selected height valueH to obtained a set of pre-selected plane, wherein each pre-selectedplane in the set of pre-selected plane meets the equation ax+by+cz+d=0,d=−h; and each adjacent height value h meets hϵ(h−σ, h+σ), σ being apredefined value, and σ being greater than or equal to the predefinedstep, and less than the predefined width;

a distance calculating sub-module, configured to calculate distancesbetween each three-dimensional point and each pre-selected plane basedon the three-dimensional point set and the set of pre-selected plane;

a support point determining sub-module, configured to determine, foreach pre-selected plane, a three-dimensional point having a distancebetween the three-dimensional point and the pre-selected plane beinggreater than a predefined support threshold as a support point of apre-selected plane;

a target plane determining sub-module, configured to determine apre-selected plane having the most support points in the set ofpre-selected planes as a target plane; and

a height determining sub-module, configured to determine an averagevalue of distances between all support points in the target plane andthe reference plane as the height of the stereo camera.

Optionally, wherein the distance calculating sub-module is furtherconfigured to:

calculate, based on the three-dimensional point set and the set ofpre-selected plane, a distance Hi′ between an i^(th) three-dimensionalpoint (x_(i), y_(i), z_(i)) and a first pre-selected plane by a seconddistance calculation formula, wherein 1≤i≤n, n being the total number ofthree-dimensional points in the three-dimensional point set, wherein thesecond distance calculation equation is as follows:

$H_{i} = \frac{{{ax}_{i} + {by}_{i} + {cz}_{i} + d}}{\sqrt{a^{2} + b^{2} + c^{2}}}$

wherein the first pre-selected plane is a pre-selected plane in the setof pre-selected plane.

Optionally, the ground image includes a plurality of contiguous groundimages captured by the stereo camera; and

the first determining module is further configured to:

perform median filtering in time domain on the plurality of contiguousground images to obtain ground images after median filtering in timedomain;

perform median filtering in space domain on each ground image aftermedian filtering in time domain to the ground images after medianfiltering in space domain; and

determine depth information of each pixel on ground images after medianfiltering in space domain.

Optionally, where the acquiring module is further configured to:

acquire the angle information of the stereo camera by an angle sensor inthe stereo camera.

Optionally, wherein the stereo camera is a binocular stereo camera or atime of flight (TOF) stereo camera.

According to a third aspect of the present disclosure, there is provideda stereo camera, comprising:

at least one processing component; and

a memory;

Wherein the memory stores at least one instruction, configured to beexecuted by the at least one processing component, and configured to beexecuted by the at least one processing component to perform theinstructions:

acquiring angle information of a stereo camera, wherein the angleinformation includes a pitch angle and a tilt angle;

capturing a ground image of a scenario where the stereo camera isdeployed;

determining depth information of each pixel on the ground image;

establishing a three-dimensional point set based on the depthinformation of each pixel on the ground image, wherein thethree-dimensional point set includes coordinate information of eachthree-dimensional point corresponding to each pixel of the ground image;and

determining the height of the stereo camera based on the angleinformation and the three-dimensional point set.

Optionally, wherein the determining the height of the stereo camerabased on the angle information and the three-dimensional point set,comprises:

determining, based on the pitch angle and the tilt angle, a referenceplane equation corresponding to a reference plane, wherein the referenceplane is parallel to a horizon plane in a world coordinate system, and acenter point of a lens of the stereo camera is within the referenceplane;

calculating distances between each three-dimensional point in thethree-dimensional point set and the reference plane to obtain a distanceset; and

determining the height of the stereo camera based on the distances inthe distance set.

Optionally, wherein the determining, based on the pitch angle and thetilt angle, a reference plane equation corresponding to a referenceplane, comprises:

determining the reference plane equation ax+by+cz=0 based on the pitchangle θ and the tilt angle φ, such that a point (a, b, c) in a cameracoordinate system meets an angle conversion equation:

${{\lbrack y\rbrack = {\left\lbrack T^{- 1} \right\rbrack \lbrack x\rbrack}};{{{wherein}\mspace{14mu}\lbrack x\rbrack} = \begin{bmatrix}x_{r} \\y_{r} \\z_{r}\end{bmatrix}}},{\lbrack y\rbrack = \begin{bmatrix}x_{c} \\y_{c} \\z_{c}\end{bmatrix}},{\lbrack T\rbrack = \begin{bmatrix}{\cos \; \phi} & {\cos \; \theta \; \sin \; \phi} & {{- \sin}\; \theta \; \sin \; \phi} \\{{- \sin}\; \phi} & {\cos \; {\theta cos}\; \phi} & {{- \sin}\; {\theta cos}\; \phi} \\0 & {\sin \; \theta} & {\cos \; \theta}\end{bmatrix}},$

[T⁻¹] is an inverse of matrix [T], (x_(c), y_(c), z_(c)) is a point inthe camera coordinate system, and (x_(y), y_(y), z_(y)) is a point inthe world coordinate system corresponding to the point (x_(c), y_(c),z_(c)) in the camera coordinate system, wherein an origin of the worldcoordinate system coincides with an origin of the camera coordinatesystem, and coordinate axes of the world coordinate system arecorrespondingly parallel to coordinate axes of the world coordinatesystem.

Optionally, wherein the calculating distances between eachthree-dimensional point in the three-dimensional point set and thereference plane to obtain a distance set, comprises:

calculating a distance H_(i) between an i^(th) three-dimensional point(x_(i), y_(i), z_(i)) and the reference plane by using a first distancecalculation equation based on the three-dimensional point set and thereference plane equation, wherein the distance set comprises thedistance H_(i), 1≤i≤n, n being the total number of three-dimensionalpoints in the three-dimensional point set, and the first distancecalculation equation is:

${H_{i} = \frac{{{ax}_{i} + {by}_{i} + {cz}_{i}}}{\sqrt{a^{2} + b^{2} + c^{2}}}};$

wherein the reference plane equation is ax+by+cz=0, a, b and c beingcoefficients of ax+by+cz=0.

Optionally, wherein the determining the height of the stereo camerabased on the distances in the distance set, comprises:

combining the distances in the distance set to obtain a target distanceset, wherein distances in the target distance set are different fromeach other, each distance corresponds a number of times, and the numberof times indicates a times count of occurrences of a correspondingdistance in the distance set; and

determining a distance corresponding a maximum number of times in thetarget distance set as the height of the stereo camera.

Optionally, wherein the reference plane equation is ax+by+cz=0, a, b andc being coefficients of ax+by+cz=0; and

wherein the determining the height of the stereo camera based on thedistances in the distance set, comprises:

forming, by a predefined width as a class width, a distance histogramaccording the distance set, wherein herein a width in a horizontal axisof each rectangular column in the distance histogram indicates adistance range, and a length in a vertical axis of each rectangularcolumn in the distance histogram indicates the number of distanceswithin the distance range;

determining a middle point of width in the horizontal axis of arectangular column having a maximum distance range in the distancehistogram as a pre-selected height value H;

traversing, by a predefined step, each adjacent height value h aroundthe pre-selected height value H to obtain a set of pre-selected plane,wherein each pre-selected plane in the set of pre-selected plane meetsthe equation ax+by+cz+d=0, d=−h; and each adjacent height value h meetshϵ(h−σ, h+σ), σ being a predefined value, and σ being greater than orequal to the predefined step, and less than the predefined width;

calculating distances between each three-dimensional point and eachpre-selected plane based on the three-dimensional point set and the setof pre-selected plane;

determining a three-dimensional point with the distance to thepre-selected plane being greater than a predefined support threshold asa support point of the pre-selected plane;

determining a pre-selected plane having the most support points in thepre-selected planes set as a target plane; and

determining an average value of distances between each support point inthe target plane and the reference plane as the height of the stereocamera.

According to a fourth aspect of the present disclosure, there isprovided a height acquisition system, comprises:

a remote control apparatus and a stereo camera; wherein the remotecontrol apparatus is configured to remotely control the stereo camera;and

the stereo camera is the stereo camera above, or the stereo camera isthe stereo camera above.

According to a fifth aspect of the present disclosure, there is provideda height acquisition system, comprising: a remote control apparatus anda stereo camera; wherein

the stereo camera is configured to:

acquire angle information of the stereo camera, wherein the angleinformation includes a pitch angle and a tilt angle;

capture a ground image of a scenario where the stereo vision camera isdeployed; and

send the angle information and the ground image to the remote controlapparatus;

the remote control apparatus is configured to:

receive the angle information and the ground image;

determine depth information of each pixel on the ground image;

establish a three-dimensional point set based on depth information ofeach pixel on the ground image, wherein the three-dimensional point setincludes coordinate information of each three-dimensional pointcorresponding to each pixel on the ground image; and

determine height of the stereo camera based on the angle information andthe three-dimensional point set.

Optionally, wherein the determine the height of the stereo camera basedon the angle information and the three-dimensional point set, comprises:

determine, based on the pitch angle and the tilt angle, a referenceplane equation corresponding to a reference plane, wherein the referenceplane is parallel to a horizon plane in a world coordinate system, and acenter point of a lens of the stereo camera is within the referenceplane;

calculate distances between each three-dimensional point in thethree-dimensional point set and the reference plane to obtain a distanceset; and

determine the height of the stereo camera based on the distances in thedistance set.

Optionally, wherein the determine, based on the pitch angle and the tiltangle, a reference plane equation corresponding to a reference plane,comprises:

determine the reference plane equation ax+by+cz=0 based on the pitchangle θ and the tilt angle φ, such that a point (a, b, c) in a cameracoordinate system meets an angle conversion equation:

${{\lbrack y\rbrack = {\left\lbrack T^{- 1} \right\rbrack \lbrack x\rbrack}};{{{wherein}\mspace{14mu}\lbrack x\rbrack} = \begin{bmatrix}x_{r} \\y_{r} \\z_{r}\end{bmatrix}}},{\lbrack y\rbrack = \begin{bmatrix}x_{c} \\y_{c} \\z_{c}\end{bmatrix}},{\lbrack T\rbrack = \begin{bmatrix}{\cos \; \phi} & {\cos \; \theta \; \sin \; \phi} & {{- \sin}\; \theta \; \sin \; \phi} \\{{- \sin}\; \phi} & {\cos \; {\theta cos}\; \phi} & {{- \sin}\; {\theta cos}\; \phi} \\0 & {\sin \; \theta} & {\cos \; \theta}\end{bmatrix}},$

[T⁻¹] is an inverse of matrix [T], (x_(c), y_(c), z_(c)) is a point inthe camera coordinate system, and (x_(y), y_(y), z_(y)) is a point inthe world coordinate system corresponding to the point (x_(c), y_(c),z_(c)) in the camera coordinate system, wherein an origin of the worldcoordinate system coincides with an origin of the camera coordinatesystem, and coordinate axes of the world coordinate system arecorrespondingly parallel to coordinate axes of the world coordinatesystem.

Optionally, wherein the calculate distances between eachthree-dimensional point in the three-dimensional point set and thereference plane to obtain a distance set, comprises:

calculate a distance H_(i) between an i^(th) three-dimensional point(x_(i), y_(i), z_(i)) and the reference plane by using a first distancecalculation equation based on the three-dimensional point set and thereference plane equation, wherein the distance set comprises thedistance H_(i), 1≤i≤n, n being the total number of three-dimensionalpoints in the three-dimensional point set, and the first distancecalculation equation is:

${H_{i} = \frac{{{ax}_{i} + {by}_{i} + {cz}_{i}}}{\sqrt{a^{2} + b^{2} + c^{2}}}};$

wherein the reference plane equation is ax+by+cz=0, a, b and c beingcoefficients of ax+by+cz=0.

Optionally, wherein the determine the height of the stereo camera basedon the distances in the distance set, comprises:

combine the distances in the distance set to obtain a target distanceset, wherein distances in the target distance set are different fromeach other, each distance corresponds a number of times, and the numberof times indicates a times count of occurrences of a correspondingdistance in the distance set; and

determine a distance corresponding a maximum number of times in thetarget distance set as the height of the stereo camera.

Optionally, wherein the reference plane equation is ax+by+cz=0, a, b andc being coefficients of ax+by+cz=0; and

wherein the determine the height of the stereo camera based on thedistances in the distance set, comprises:

form, by a predefined width as a class width, a distance histogramaccording the distance set, wherein herein a width in a horizontal axisof each rectangular column in the distance histogram indicates adistance range, and a length in a vertical axis of each rectangularcolumn in the distance histogram indicates the number of distanceswithin the distance range;

determine a middle point of width in the horizontal axis of arectangular column having a maximum distance range in the distancehistogram as a pre-selected height value H;

traverse, by a predefined step, each adjacent height value h around thepre-selected height value H to obtain a set of pre-selected plane,wherein each pre-selected plane in the set of pre-selected plane meetsthe equation ax+by+cz+d=0, d=−h; and each adjacent height value h meetshϵ(h−σ, h+σ), σ being a predefined value, and σ being greater than orequal to the predefined step, and less than the predefined width;

calculate distances between each three-dimensional point and eachpre-selected plane based on the three-dimensional point set and the setof pre-selected plane;

determine a three-dimensional point with the distance to thepre-selected plane being greater than a predefined support threshold asa support point of the pre-selected plane;

determine a pre-selected plane having the most support points in thepre-selected planes set as a target plane; and

determine an average value of distances between each support point inthe target plane and the reference plane as the height of the stereocamera.

According to a fifth aspect of the present disclosure, there is provideda non-volatile computer-readable storage medium, which stores codeinstructions; wherein the code instructions are executed by a processorto perform the height acquisition method of a stereo camera as definedin the first aspect.

The technical solutions according to examples of the present disclosuremay achieve the following beneficial effects:

In summary, examples of the present disclosure provide a stereo camera,method and system for acquiring a height of stereo camera thereof, theground image of the scenario where the stereo vision camera is deployedis captured, then the three-dimensional point set recording coordinateinformation of each three-dimensional point corresponding to each pixelon the ground image is determined based on depth information of eachpixel on the ground image, and the height of the stereo camera isdetermined based on the angle information and the three-dimensionalpoint set. In this way, the stereo camera automatically determines theheight thereof without defining an external reference structure, suchthat the operation complexity is lowered, and the cost for determiningthe height is reduced.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are intended to limit the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the technical solutions in examples of the presentmore clearly, the following briefly introduces the accompanying drawingsrequired for describing the examples. Apparently, the accompanyingdrawings in the following description show merely some examples of thepresent disclosure, and a person of ordinary skill in the art may alsoderive other drawings from these accompanying drawings without creativeefforts.

FIG. 1 is a schematic diagram of an implementation scenario of a heightacquisition method of a stereo camera according to examples of thepresent disclosure;

FIG. 2 is a flowchart of a height acquisition method of a stereo cameraaccording to examples of the present disclosure;

FIG. 3-1 is a flowchart of another height acquisition method of a stereocamera according to examples of the present disclosure;

FIG. 3-2 is a schematic diagram of a scenario image captured by a stereocamera according to examples of the present disclosure;

FIG. 3-3 is a schematic flowchart of a method for determining a heightof a stereo camera based on angle information and a three-dimensionalpoint set according to examples of the present disclosure;

FIG. 3-4 is a schematic diagram of a relation between a world coordinatesystem and a camera coordinate system according to examples of thepresent disclosure;

FIG. 3-5 illustrates schematic diagrams of a histogram according toexamples of the present disclosure;

FIG. 4 is a schematic structural block diagram of a stereo cameraaccording to examples of the present disclosure; and

FIG. 5 is a schematic structural block diagram of another stereo cameraaccording to examples of the present disclosure.

The accompanying drawings herein, which are incorporated into andconstitute a part of the specification, illustrate examples consistentwith the present disclosure, and together with the specification, serveto explain the principles of the present disclosure.

DETAILED DESCRIPTION

For clearer descriptions of the objectives, technical solutions andadvantages of the present disclosure, the present disclosure is furtherdescribed in detail with reference to the accompanying drawings.Apparently, examples described hereinafter are merely some exemplaryones for illustrating the present disclosure, instead of all theexamples. Based on the examples of the present disclosure, all otherexamples derived by persons of ordinary skill in the art shall fallwithin the protection scope of the present disclosure.

The terminology used herein is for the purpose of describing particularexamples only and is not intended to be limiting of examples. As usedherein, the singular forms “a,” “an” and “the” are intended to includethe plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises,”“comprising,” “includes” and/or “including,” when used herein, specifythe presence of stated features, integers, steps, operations, elementsand/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components and/or groups thereof.

It should also be noted that in some alternative implementations, thefunctions/acts noted may occur out of the order noted in the figures.For example, two functions or acts shown in succession may in fact beexecuted concurrently or may sometimes be executed in the reverse order,depending upon the functionality/acts involved.

In a conventional stereo vision camera, before image capture andanalysis, camera parameters need to be predefined, wherein the cameraparameters may include an internal parameter (abbr.: IP) and an externalparameter (abbr.: EP). The external parameter may include at least oneof the parameter: a pitch angle, a tilt angle and a height. In theconventional methods for determining a height of a stereo vision camera,an external reference structure needs to be defined. For example, acalibration plate may be arranged to keep coincidence with the worldcoordinate system to acquire coordinates of characteristic points on thecalibration plate. In addition, the calibration plate needs to beremoved, such that central point three-dimensional points sampling isperformed at different positions on the calibration plate, and theheight of the stereo vision camera is determined by calculating aconversion matrix.

However, determining the height by defining the external referencestructure is complicated in operation and needs a high cost.

Referring to FIG. 1, FIG. 1 is a schematic diagram of an implementationscenario of a height acquisition method of a stereo camera according toexamples of the present disclosure. In this scenario, a stereo camera110 is located indoors or outdoors.

Before capturing and analyzing an image, a camera parameter of aconventional stereo camera may be predefined, wherein the cameraparameter may include an internal parameter (abbr.: IP) and/or anexternal parameter (abbr.: EP). The external parameter may include anyone of the following parameters: a pitch angle, a tilt angle and aheight. Calibration of the external parameters of the stereo camera is apremise and basis for three-dimensional measurement of the stereocamera, and is one of the most important parts for ensuring precision ofan image processing result of the stereo camera. An incorrect cameraexternal parameter may interfere the visual analysis for the stereocamera. As illustrated in FIG. 1, height of the stereo camera is heightHt thereof in a world coordinate system, which may be generally adistance from a central point of a lens of the stereo camera to ahorizon W in the world coordinate system. The central point is an originof a camera coordinate system of the stereo camera. The cameracoordinate system is a plane coordinate system, and the horizon W is aplane extracted from the ground.

In examples of the present disclosure, the stereo camera captures aground image of a scenario where the stereo camera is deployed, and theheight of the stereo camera is determined based on the ground image andpre-acquired angle information. The stereo camera may include aprocessing component, an angle sensor (also known as a gyroscope) and alens. The processing component may be a processor or a processing chip.The lens is configured to capture the ground image of the scenario wherethe stereo camera is deployed. The processing component is configured todetermine the height of the stereo camera based on the ground image andthe angle information pre-acquired by the angle sensor.

As illustrated in FIG. 2, examples of the present disclosure provide amethod for acquiring a height of a stereo camera, which is applied tothe stereo camera as illustrated in FIG. 1. The method includes:

Step 201: Angle information of a stereo camera is acquired, wherein theangle information includes a pitch angle and a tilt angle;

Step 202: A ground image of a scenario where the stereo camera isdeployed is captured;

Step 203: Depth information of each pixel on the ground image isdetermined;

Step 204: A three-dimensional point set based on depth information ofeach pixel on the ground image is established, wherein thethree-dimensional point set includes coordinate information of eachthree-dimensional point corresponding to each pixel of the ground image;and

Step 205: The height of the stereo camera is determined based on theangle information and the three-dimensional point set.

In examples of the disclosure, the act above may in fact be executedconcurrently or may sometimes be executed in the reverse order,depending upon the acts involved.

In summary, based on the method for acquiring the height of a stereocamera according to examples of the present disclosure, the ground imageof the scenario where the stereo camera is deployed is captured, and thethree-dimensional point set including coordinate information of eachthree-dimensional point corresponding to each pixel on the ground imageis determined based on depth information of each pixel on the groundimage, and the height of the stereo camera is determined based on theangle information and the three-dimensional point set. In this way, thestereo camera may automatically determine the height without adefinition for an external reference structure, and thereby lowing theoperation complexity, and reducing cost for determining the height.

As illustrated in FIG. 3-1, examples of the present disclosure provide amethod for acquiring height of a stereo camera, which is applied to thestereo camera as illustrated in FIG. 1. According to the method, theheight of the stereo camera in a world coordinate system may bedetermined. The stereo camera may be a binocular stereo camera, a TOFstereo camera or the like, that is capable of acquiring stereothree-dimensional information. The method includes the following steps:

Step 301: The stereo camera acquires angle information of the stereocamera by an angle sensor which is in the stereo camera.

In examples of the present disclosure, the angle information includes apitch angle and a tilt angle. The angle sensor may be arranged in thestereo camera to measure angle information of the stereo camera.Precisions of a pitch angle and a tilt angle acquired by the anglesensor are generally high. The angle sensor may be an angle sensor chip,a highly integrated chip may save space in the stereo camera.

Step 302: The stereo camera captures, by a lens of the stereo camera, aground image of the scenario where the stereo camera is deployed.

In examples of the present disclosure, the stereo camera may bemaintained at a current state, and may automatically capture a scenarioimage of a scenario where the stereo camera is deployed. The scenarioimage includes a ground image. Further, the scenario image includes oneimage, or a plurality of contiguous images, or a plurality of frames ina video. The stereo camera may extract a ground image from the scenarioimage, and perform following processing on the image, or the stereocamera may directly perform following processing on the ground image inthe scenario image.

Step 303: The stereo camera determines depth information of each pixelon the ground image.

A depth of an image refers to the number of bits used for storing eachpixel in the image. The depth of an image may be used to measure a colorresolution of the image. The depth information is also information fordescribing the depth of the image.

The ground image (for example, a parallax image captured by a binocularstereo camera, or a depth image captured by a TOF stereo camera)acquired by the stereo camera may contain noise. The acquired groundimage may be pre-processed to ensure accuracy of the depth information.

For example, in step 302, the stereo camera may capture a plurality ofground images, and generally the stereo camera may continuously capturewithin a predefined time duration to obtain a plurality of scenarioimages, and thus to obtain a plurality of ground images (each groundimage may be a scenario image, or each ground image may be an image of aground region in the corresponding scenario image). In examples of thepresent disclosure, a video may also be captured, and a plurality ofcontiguous frames in the video may be used as the scenario images toobtain a plurality of ground images. Then, a median filtering in timedomain is performed on the plurality of contiguous ground images toobtain a plurality of ground images after median filtering in timedomain; then a median filtering in space domain is performed on theplurality of ground images after median filtering in time domain toobtain a plurality of ground images after median filtering in spacedomain; and then depth information of each pixel on the ground imagesafter median filtering in space domain is determined.

In examples of the present disclosure, wherein performing the medianfiltering in time domain on the plurality of contiguous ground images,refers to performing the median filtering in time domain on acorresponding pixel on each of the plurality of contiguous groundimages, until the median filtering in time domain is performed on eachpixel on ground images.

The median filtering in time domain may filter out information ofinaccurate parallax caused by incorrect parallax calculation for animage, and the median filtering in space domain may filter outinformation of failure to calculate the parallax at a specific positionin a specific scenario.

It should be noted that whether to perform the median filtering in timedomain and the median filtering in space domain is determined based onthe quality of an imaging the stereo camera captured. If the stereocamera has better performance and high precision, and the captured imagemeets the calculation requirement, the median filtering in time domainand the median filtering in space domain are not necessary. If thestereo camera has poor performance and low precision, and the capturedimage fails to satisfy the calculation requirement, the median filteringin time domain and/or the median filtering in space domain is necessary.

Further, the process of determining depth information of each pixel onthe ground image by the stereo camera may be implemented by conventionalmethods. For example, when the stereo camera is a binocular stereocamera, a synchronous exposure image may be obtained by using thecalibrated two cameras based on the bionics principle, and thenthree-dimensional depth information of each pixel on the acquiredtwo-dimensional image is calculated.

Step 304: The stereo camera establishes a three-dimensional point setbased on depth information of each pixel on the ground image, whereinthe three-dimensional point set includes coordinate information of eachthree-dimensional point corresponding to each pixel on the ground image.

The stereo camera may determine coordinate information of eachthree-dimensional point based on the depth information of correspondingpixel on the ground image, and add the coordinate information of eachthree-dimensional point in the three-dimensional point set. Thecoordinate information may be coordinate values of eachthree-dimensional point in the world coordinate system. For example,assuming that the scenario image captured by the stereo camera in step302 is as illustrated in FIG. 3-2, the ground image is an imagecorresponding to a region M (that is, a dotted-line region in FIG. 3-2),then the value of the three-dimensional point corresponding to the pixelx in the world coordinate system in a practical scenario of the scenarioimage may be determined based on the depth information of any pixel x inthe region M.

It should be noted that when the stereo camera determines thethree-dimensional point set based on the depth information of each pixelon the ground image, the each three-dimensional point may be screened inadvance to exclude three-dimensional points having unqualifiedcoordinate information to obtain a more accurate three-dimensional pointset. In this way, the accuracy of the height of the stereo camera thatis subsequently determined is improved.

For example, when the stereo camera is a binocular stereo camera, theground image is a parallax image, and the stereo camera may determinewhether the parallax corresponding to each pixel on the ground image iswithin a predefined parallax range. When the parallax corresponding to apixel is not within the predefined parallax range, the pixel isexcluded, that is, the coordinate information of the three-dimensionalpoint corresponding to the pixel is not added to the three-dimensionalpoint set. When the parallax corresponding to a pixel is within thepredefined parallax range, the coordinate information of thethree-dimensional point corresponding to the pixel is determined, andthe coordinate information of the three-dimensional point is added tothe three-dimensional point set.

For another example, when the stereo camera is a TOF stereo camera, theground image is a depth image, and the stereo camera may determinewhether the depth corresponding to each pixel on the ground image iswithin a predefined depth range. When the depth corresponding to a pixelis not within the predefined depth range, the pixel is excluded, thatis, the coordinate information of the three-dimensional pointcorresponding to the pixel is not added to the three-dimensional pointset. When the depth corresponding to a pixel is within the predefineddepth range, the coordinate information of the three-dimensional pointcorresponding to the pixel is determined, and the coordinate informationof the three-dimensional point is added to the three-dimensional pointset.

Step 305: The stereo camera determines the height of the stereo camerabased on the angle information and the three-dimensional point set.

For example, the method for determining the height of the stereo camerabased on the angle information and the three-dimensional point set maybe as illustrated in FIG. 3-3, and include the following steps:

Step 3051: A reference plane equation corresponding to a reference planeis determined based on the pitch angle and the tilt angle, wherein thereference plane is parallel to a horizon plane in a world coordinatesystem, and a center point of a lens of the stereo camera is within thereference plane.

Referring to FIG. 3-4, FIG. 3-4 is a schematic diagram of a relationbetween a world coordinate system and a camera coordinate system. Asillustrated in FIG. 3-4, assuming that variables (x, y, z) respectivelyrepresent coordinate axes of the stereo camera in the world coordinatesystem; variables (x_(c), y_(c), z_(c)) respectively representcoordinate axes of the stereo camera in the camera coordinate system,and variables (x_(r), y_(r), z_(r)) respectively represent coordinateaxes of the stereo camera in a world reference coordinate system,wherein the world reference coordinate system is a coordinate systemwhen the world coordinate system is translated along a positivedirection of the y axis thereof to coincide with the origin of thecamera coordinate system. Variables (x′_(c), y′_(c), z′_(c)) represent acoordinate system when the camera coordinate system is translated alonga negative direction of y axis thereof to coincide with the origin ofthe world coordinate system, wherein the origin of the world referencecoordinate system coincides with the origin of the camera coordinatesystem, and the coordinate axes of the world reference coordinate systemare parallel to the coordinate axes of the world coordinate system. Boththe origin of the world reference coordinate system and the origin ofthe camera coordinate system are the central point of the lens of thestereo camera.

Based on the pitch angle and the tilt angle of the stereo camera in thecurrent state acquired by the angle sensor, the following angleconversion equation may be determined according to the Euler's equationand the angle conversion relation in the world reference coordinatesystem:

$\begin{bmatrix}x_{r} \\y_{r} \\z_{r}\end{bmatrix} = {\begin{bmatrix}{\cos \; \phi} & {\cos \; \theta \; \sin \; \phi} & {{- \sin}\; \theta \; \sin \; \phi} \\{{- \sin}\; \phi} & {\cos \; {\theta cos}\; \phi} & {{- \sin}\; {\theta cos}\; \phi} \\0 & {\sin \; \theta} & {\cos \; \theta}\end{bmatrix}\begin{bmatrix}x_{c} \\y_{c} \\z_{c}\end{bmatrix}}$

This angle conversion equation may be written as [x]=[T][y] forsimplicity.

An inverse transform is performed on the angle conversion equation toobtain [y]=[T⁻¹][x].

In above formulae, assuming that (x_(c), y_(c), z_(c)) is a point in thecamera coordinate system, (x_(r), y_(r), z_(r)) is a point in the worldreference coordinate system corresponding to the point (x_(c), y_(c),z_(c)) in the camera coordinate system, coordinate conversion betweentwo coordinate systems with the same origin is a relation of angleconversion, wherein θ represents the pitch angel of the stereo camera, φrepresents the tilt angle of the stereo camera,

${\lbrack x\rbrack = \begin{bmatrix}x_{r} \\y_{r} \\z_{r}\end{bmatrix}},{\lbrack y\rbrack = \begin{bmatrix}x_{c} \\y_{c} \\z_{c}\end{bmatrix}},{\lbrack T\rbrack = \begin{bmatrix}{\cos \; \phi} & {\cos \; \theta \; \sin \; \phi} & {{- \sin}\; \theta \; \sin \; \phi} \\{{- \sin}\; \phi} & {\cos \; {\theta cos}\; \phi} & {{- \sin}\; {\theta cos}\; \phi} \\0 & {\sin \; \theta} & {\cos \; \theta}\end{bmatrix}},$

and [T⁻¹] is an inverse of matrix [T].

A unit normal vector of the world reference coordinate system is (0, 1,0), and a start point of the vector (0, 1, 0) in the world referencecoordinate system and the camera coordinate system are both the origin(0, 0, 0), and an end point of the vector (0, 1, 0) in the cameracoordinate system may be obtained by a formula: y=[T⁻¹][x]. Assumingthat finally in the camera coordinate system, a point corresponding tothe end position of the vector (0, 1, 0) is (a, b, c), then a unitnormal vector of the plane corresponding to the camera coordinate systemis {right arrow over (n)}=(a,b,c), and hence a reference plane equationax+by+cz=0 of a reference plane P1 in the camera coordinate system maybe obtained. The reference plane P1 is parallel to a horizon plane P2 ofthe world coordinate system.

As seen from the above, the process of determining a reference planeequation corresponding to a reference plane based on the pitch angle andthe tilt angle includes:

determining the reference plane equation ax+by+cz=0 based on the pitchangle θ and the tilt angle φ, such that a point (a, b, c) in a cameracoordinate system meets an angle conversion equation as follows:

$\lbrack y\rbrack = {{\left\lbrack T^{- 1} \right\rbrack \lbrack x\rbrack}\mspace{14mu} {wherein}\mspace{11mu} {\quad\; {{\lbrack x\rbrack = \begin{bmatrix}x_{r} \\y_{r} \\z_{r}\end{bmatrix}},{\lbrack y\rbrack = \left\lbrack \begin{matrix}x_{c} \\y_{c} \\z_{c}\end{matrix} \right\rbrack},{\lbrack T\rbrack = \left\lbrack \begin{matrix}{\cos \; \phi} & {\cos \; \theta \; \sin \; \phi} & {{- \sin}\; \theta \; \sin \; \phi} \\{{- \sin}\; \phi} & {\cos \; {\theta cos}\; \phi} & {{- \sin}\; {\theta cos}\; \phi} \\0 & {\sin \; \theta} & {\cos \; \theta}\end{matrix} \right\rbrack},}}}$

[T⁻¹] is an inverse of matrix [T], (x_(c), y_(c), z_(c)) is a point inthe camera coordinate system, and (x_(y), y_(y), z_(y)) is a point inthe world coordinate system corresponding to the point (x_(c), y_(c),z_(c)) in the camera coordinate system.

For example, assuming that the calculated point (a, b, c) in the cameracoordinate system is (0.408, 0.577, 0.707), then the reference planeequation is 0.408x+0.577y+0.707z=0.

Step 3052: Distances between each three-dimensional point in thethree-dimensional point set and the reference plane are calculated toobtain a distance set.

The distance sent includes a plurality of distances corresponding to thethree-dimensional point set. Optionally, based on the three-dimensionalpoint set and the reference plane equation, a distance H_(i) between ani^(th) three-dimensional point (x_(i), y_(i), z_(i)) and the referenceplane is calculated by a first distance calculation formula, and theabove distance set includes the distance Hi, 1≤i≤n, wherein n is thetotal number of three-dimensional points in the three-dimensional pointset, and the first calculation equation is as follows:

$H_{i} = \frac{{{ax}_{i} + {by}_{i} + {cz}_{i}}}{\sqrt{a^{2} + b^{2} + c^{2}}}$

wherein the reference plane equation is ax+by+cz=0; a, b and c beingcoefficients of ax+by+cz=0.

For example, assuming that the reference plane equation is x+2y+3z=0,and a coordinate of a point in the three-dimensional point set is (2, 2,2), then it is calculated by using the first calculation equation thatthe distance between the point and the reference plane is

$\frac{{{1*2} + {2*2} + {3*2}}}{\sqrt{1^{2} + 2^{2} + 3^{2}}} = {\frac{12}{\sqrt{14}}.}$

Step 3503: The height of the stereo camera is determined based on amaximum distance in the distance set.

In examples of the present disclosure, the method for determining theheight of the stereo camera based on the maximum distance in thedistance set may be performed in a plurality of implementation ways. Thefollowing two implementation manners are described as examples of thepresent disclosure:

In a first implementation manner, the maximum distance in the distanceset may be directly determined as the height of the stereo camera, thatis, the maximum distance in distances between each three-dimensionalpoint and the reference plane is determined as the height of the stereocamera. The first implementation manner for determining the height isrelatively simple.

In a second implementation manner, the height of the stereo camera maybe determined based on a histogram. The second implementation manner fordetermining the height achieves a high precision. The secondimplementation manner includes the following steps:

Step a: A predefined width is determined as a class width, and then adistance histogram is established by counting the distance set, whereina width in a horizontal axis of each rectangular column in the distancehistogram indicates a distance range, and a length in a vertical axis ofeach rectangular column in the distance histogram indicates the numberof distances within the distance range.

It should be noted that the number of distances within the distancerange is the number of corresponding distances in three-dimensionalpoints within the corresponding distance range.

Since the ground image includes a plurality of pixels, that is, aplurality of three-dimensional points, the height of the stereo cameramay be determined based on the distances between each of the pluralityof three-dimensional points and the reference plane, wherein a visualmanner to count distance is the distance histogram. As illustrated inFIG. 3-5, assuming that the predefined width is 10 cm, then the classwidth is determined as 10 cm, and the class width may be determined as astep for drawing the histogram, and the distance histogram isestablished by counting the distance set. The horizontal axis of thehistogram is in centimeters; (in examples of the present disclosure, theunit of the horizontal axis of the histogram may be defined according tothe specific situation, and FIG. 3-5 is only an illustrativedescription). The vertical axis of the histogram is in pieces. The widthin the horizontal axis of each rectangular column in the histogramrepresents the distance range, and the length in the vertical axis ofeach rectangular column in the histogram represents the number ofdistances in the distance set within the distance range. For example,the width of a rectangular column L in the horizontal axis represents adistance range is: 50 to 60 cm, and the length in the vertical axis ofthe rectangular column represents the number of distances in thedistance sent within the distance range of 50 to 60 cm is: 60.

Step b: A middle point of the width in the horizontal axis of arectangular column, corresponding to a maximum distance range in thedistance histogram, is determined as a pre-selected height value H.

In examples of the present disclosure, the rectangular column includingthe maxim distance is a rectangular column corresponding to a maximumdistance range. For example, as illustrated in FIG. 3-5, the rectangularcolumn including the maximum distance is a rectangular column Q, (thatis, the rectangular column corresponding to the maximum distance rangeis the rectangular column Q), the corresponding distance range of therectangular column Q is 90 to 100 cm, and a middle point of width in thehorizontal axis of the rectangular column Q is 95. In this case, thepre-selected height value H is 95. In examples of the presentdisclosure, if the stereo camera does not request a strict requirementon the precision, the pre-selected height value may be directlydetermined as height value of the external parameters.

Step c: A set of pre-selected plane is determined by traversing, by apredefined step, each adjacent height value h around the pre-selectedheight value H, wherein each pre-selected plane in the set ofpre-selected plane meets the equation ax+by+cz+d=0, d=−h; and eachadjacent height value h meets h□(h−σ, h+σ), σ being a predefined value,and σ being greater than or equal to the predefined step, and less thanthe predefined width. For example, if the predefined step is f and thepredefined width is g, f≤σ<g.

Step b is actually a rough selection of the height, and step c isactually an accurate selection of the height. For example, assuming thatσ is 2, H is 95 and the predefined step is 1, then h□(95−2, 95+2), thatis, h□(93, 97); and assuming that the reference plane equationax+by+cz=0 is x+2y+3z=0, then the set of pre-selected plane includes:x+2y+3z−93=0, x+2y+3z−94=0, x+2y+3z−95=0, x+2y+3z−96=0 and x+2y+3z−97=0.

Step d: Distances between each three-dimensional point and eachpre-selected plane are obtained based on the three-dimensional point setand the set of pre-selected plane.

Optionally, assuming that a first pre-selected plane is a pre-selectedplane in the set of pre-selected plane, then step d may include:calculating a distance H_(i)′ between a i^(th) three-dimensional point(x_(i), y_(i), z_(i)) and the first pre-selected plane by a secondcalculation equation based on the three-dimensional point set and theset of pre-selected plane, wherein 1≤i≤n, n being the total number ofthree-dimensional points in the three-dimensional point set, and thesecond distance calculation equation is as follows:

$H_{i}^{\prime} = {\frac{{{ax}_{i} + {by}_{i} + {cz}_{i} + d}}{\sqrt{a^{2} + b^{2} + c^{2}}}.}$

Optionally, distances between each three-dimensional point in thethree-dimensional point set and each pre-selected plane in the set ofpre-selected plane may be re-counted by the second distance calculationequation above.

For example, assuming that the equation corresponding to the firstpre-selected plan is x+2y+3z−96=0, and a coordinate of a point in thethree-dimensional point set is (2, 2, 2), then the distance between thepoint to the first pre-selected plane determined by the equationx+2y+3z−96=0 is:

$\frac{{{1*2} + {2*2} + {3*2} - 96}}{\sqrt{1^{2} + 2^{2} + 3^{2}}} = {\frac{84}{\sqrt{14}}.}$

Step e: For each pre-selected plane, a three-dimensional point having adistance between the three-dimensional point and the pre-selected planebeing greater than a predefined support threshold is determined as asupport point of the pre-selected plane.

For example, assuming that the predefined support threshold is h_(t),and a distance H_(i)′ between the i^(th) three-dimensional point (x_(i),y_(i), z_(i)) and the first pre-selected plane is obtained by the seconddistance calculation formula, Hi′>h_(t), and the point (x_(i), y_(i),z_(i)) is a support point of the first pre-selected plane ax+by+cz+d=0.

Step f: A pre-selected plane having the largest number of support pointsin the set of pre-selected plane is determined as a target plane.

Since the conventional ground is contiguous, if a pre-selected plane hasthe largest number of support points, the three-dimensional point aremore densely distributed in the pre-selected plane, and the pre-selectedplane is more approximate to the ground of the world coordinate system.Therefore, the pre-selected plane having the largest number of supportpoints in the set of pre-selected plane may be determined as the targetplane. The target plane may represent the horizon plane of the worldcoordinate system.

Step g: An average value of distances between all the support points inthe target plane and the reference plane is determined as the height ofthe stereo camera.

In step a to step g, the pre-selected height value is firstly determinedbased on the distance set by drawing a histogram, then the set ofpre-selected plane is determined based on the pre-selected height valueand the target plane representing the ground of the world coordinatesystem is determined, and finally an average value of the distancesbetween each support point in the target plane and the reference planeis determined as the height of the stereo camera. According to thismethod, a rough selection of the height is performed first, and then anaccurate selection of the height is performed. In this way, the heightof the stereo camera obtained has a high accuracy, and no dedicatedexternal reference structure needs to be arranged.

In examples of the present disclosure, the above steps 303 to 305 mayalso be performed by a remote control device. For example, after thestereo camera acquires the angle information and the ground image of thestereo camera through steps 301 and 302, the angle information and theground image may be sent to the remote control apparatus. The remotecontrol apparatus determines depth information of each pixel on a groundimage, and then determines the three-dimensional point set based ondepth information of each pixel on the ground image, and determines theheight of the stereo camera based on the angle information and thethree-dimensional point set. The remote control apparatus may be acomputer or a server or the like device.

In summary, examples of the present disclosure provide a method foracquiring height of a stereo camera, the ground image of the scenariowhere the stereo camera is deployed is captured, the three-dimensionalpoint set which includes coordinate information of eachthree-dimensional point corresponding to each pixel on the ground imageis determined based on depth information of each pixel on the groundimage, and the height of the stereo camera is determined based on theangle information and the three-dimensional point set. In this way, thestereo camera may determine the height automatically thereof withoutdefining an external reference structure, such that the operationcomplexity is lowered, and the cost for determining the height isreduced. In addition, in examples of the present disclosure, as long asthe image captured by the stereo camera include the ground image, thestereo camera may determine the height by referencing the ground imagethereof. The way of determining the external parameters is concise, andhas high robustness.

Further, since during determination of the height of the stereo camera,the external reference structure does not need to be set up, theoperating personnel may not handle the on-site environment. Therefore,the staff does not need to handle the environment, and does not need tobe in the vicinity of the stereo camera, and thereby the stereo cameracould be controlled remotely.

As illustrated in FIG. 4, examples of the present disclosure provide astereo camera 40, the stereo camera 40 includes:

an acquiring module 401, configured to acquire angle information of thestereo camera, wherein the angle information includes a pitch angle anda tilt angle;

a capturing module 402, configured to capture a ground image of ascenario where the stereo camera is deployed;

a first determining module 403, configured to determine depthinformation of each pixel on the ground image;

an establishing module 404, configured to establish a three-dimensionalpoint set based on depth information of each pixel on the ground image,wherein the three-dimensional point set includes coordinate informationof each three-dimensional point corresponding to each pixel on theground image; and

a second determining module 405, configured to determine height of thestereo camera based on the angle information and the three-dimensionalpoint set.

The second determining module 405 includes:

a first determining sub-module, configured to determine a referenceplane equation corresponding to a reference plane based on the pitchangle and the tilt angle, wherein the reference plane is parallel to ahorizon plane in a world coordinate system, and a center point of a lensof the stereo camera is within the reference plane.

a calculating sub-module, configured to calculate distances between eachthree-dimensional point in the three-dimensional point set and thereference plane to obtain a distance set; and

a second determining module, configured to determine the height of thestereo camera based on a maximum distance in the distance set.

Optionally, the first determining sub-module is further configured to:

determine the reference plane equation ax+by+cz=0 based on the pitchangle θ and the tilt angle φ, such that a point (a, b, c) in a cameracoordinate system meets an angle conversion equation as follows:

${\lbrack y\rbrack = {{{\left\lbrack T^{- 1} \right\rbrack \lbrack x\rbrack}\mspace{14mu} {{wherein}\mspace{14mu}\lbrack x\rbrack}} = \begin{bmatrix}x_{r} \\y_{r} \\z_{r}\end{bmatrix}}},{\quad{{\lbrack y\rbrack = \begin{bmatrix}x_{c} \\y_{c} \\z_{c}\end{bmatrix}},{\lbrack T\rbrack = \begin{bmatrix}{\cos \; \phi} & {\cos \; {\theta sin}\; \phi} & {{- \sin}\; {\theta sin}\; \phi} \\{{- \sin}\; \phi} & {\cos \; {\theta cos\phi}} & {{- \sin}\; {\theta cos}\; \phi} \\0 & {\sin \; \theta} & {\cos \; \theta}\end{bmatrix}},}}$

[T⁻¹] is an inverse of matrix [T], (x_(c), y_(c), z_(c)) is a point inthe camera coordinate system, (x_(y), y_(y), z_(y)) is a point in theworld coordinate system corresponding to the point (x_(c), y_(c), z_(c))in the camera coordinate system, an origin of the world coordinatesystem coincides with an origin of the camera coordinate system, andcoordinate axes of the world coordinate system are correspondinglyparallel to coordinate axes of the world coordinate system.

Optionally, the calculating sub-module is further configured to:

calculate a distance Hi between an i^(th) three-dimensional point(x_(i), y_(i), z_(i)) and the reference plan by a first distancecalculation equation based on the three-dimensional point set and thereference plane equation, wherein the distance set includes the distanceHi, 1≤i≤n, n being the total number of three-dimensional points in thethree-dimensional point set, and the first distance calculation equationis as follows:

$H_{i} = \frac{{{ax}_{i} + {by}_{i} + {cz}_{i}}}{\sqrt{a^{2} + b^{2} + c^{2}}}$

wherein the reference plane equation is ax+by+cz=0, a, b and c beingcoefficients of ax+by+cz=0.

Optionally, the second determining sub-module is further configured to:

combine distances in the distance set to obtain a target distance set,wherein value of each distance in the target distance set are differentfrom each other, each distance has a number of times indicating numberof a same distance in the distance set; and

determine a distance having a maximum number of times in the targetdistance set as the height of the stereo camera.

Optionally, the reference plane equation is ax+by+cz=0, a, b and c beingcoefficients of ax+by+cz=0.

The second determining sub-module includes:

a histogram establishing sub-module, configured to count the distanceset to establish a distance histogram by using a predefined width as aclass width. Wherein a width in a horizontal axis of each rectangularcolumn in the distance histogram indicates a distance range, and alength in a vertical axis of each rectangular column in the distancehistogram indicates the number of distances within the distance range;

a pre-selected value determining sub-module, configured to determine amiddle point of width in the horizontal axis of a rectangular columncorresponding to a maximum distance range in the distance histogram as apre-selected height value H;

a set determining sub-module, configured to traverse, by a predefinedstep, each adjacent height value h around the pre-selected height valueH to obtained a set of pre-selected plane, wherein each pre-selectedplane in the set of pre-selected plane meets the equation ax+by+cz+d=0,d=−h; and each adjacent height value h meets h□(h−σ, h+σ), σ being apredefined value, and σ being greater than or equal to the predefinedstep, and less than the predefined width;

a distance calculating sub-module, configured to calculate distancesbetween each three-dimensional point and each pre-selected plane basedon the three-dimensional point set and the set of pre-selected plane;

a support point determining sub-module, configured to determine, foreach pre-selected plane, a three-dimensional point having a distancebetween the three-dimensional point and the pre-selected plane beinggreater than a predefined support threshold as a support point of apre-selected plane;

a target plane determining sub-module, configured to determine apre-selected plane having the most support points in the set ofpre-selected planes as a target plane; and

a height determining sub-module, configured to determine an averagevalue of distances between each support point in the target plane andthe reference plane as the height of the stereo camera.

Optionally, the distance calculating sub-module is further configuredto:

calculate, based on the three-dimensional point set and the set ofpre-selected plane, a distance Hi′ between an i^(th) three-dimensionalpoint (x_(i), y_(i), z) and a first pre-selected plane by a seconddistance calculation formula, wherein 1≤i≤n, n being the total number ofthree-dimensional points in the three-dimensional point set, wherein thesecond distance calculation equation is as follows:

$H_{i}^{\prime} = \frac{{{ax}_{i} + {by}_{i} + {cz}_{i} + d}}{\sqrt{a^{2} + b^{2} + c^{2}}}$

wherein the first pre-selected plane is a pre-selected plane in the setof pre-selected plane.

Optionally, the ground image includes a plurality of contiguous groundimages captured by the stereo camera; and

the first determining module 403 is further configured to:

perform median filtering in time domain on the plurality of contiguousground images to obtain ground images after median filtering in timedomain;

perform median filtering in space domain on each ground image aftermedian filtering in time domain to ground images after median filteringin space domain; and

determine depth information of each pixel on ground images after medianfiltering in space domain.

Optionally, the acquiring module 401 is further configured to:

acquire the angle information of the stereo camera by an angle sensor inthe stereo camera.

With respect to the apparatus in above examples, details aboutperforming corresponding acts by different modules have been describedin examples of the method, which are not given herein any further.

In summary, in the stereo camera according to examples of the presentdisclosure, the capturing module captures a ground image of a scenariowhere the stereo camera is deployed, the establishing module establishesthe three-dimensional point set including coordinate information of eachthree-dimensional point corresponding to each pixel on the ground image,and the second determining module determines the height of the stereocamera based on the angle information and the three-dimensional pointset. In this way, the stereo camera may determine the heightautomatically thereof without defining an external reference structure,such that the operation complexity is lowered, and the cost fordetermining the height is reduced.

As illustrated in FIG. 5, examples of the present disclosure provide astereo camera 50. The stereo camera 50 includes:

an angle acquiring module 501, configured to acquire angle informationof the stereo camera, wherein the angle information includes a pitchangle and a tilt angle;

a camera 502, configured to capture a ground image of a scenario wherethe stereo camera is deployed; and

a processor 503, configured to determine depth information of each pixelon the ground image.

The processor 503 is further configured to establish a three-dimensionalpoint set based on depth information of each pixel on the ground image,wherein the three-dimensional point set includes coordinate informationof each three-dimensional point corresponding to each pixel on theground image.

The processor 503 is further configured to determine height of thestereo camera based on the angle information and the three-dimensionalpoint set.

Optionally, the processor 503 is further configured to:

determine a reference plane equation corresponding to a reference planebased on the pitch angle and the tilt angle, wherein the reference planeis parallel to a the horizon in a world coordinate system, and a centerpoint of a lens of the stereo camera is within the reference plane;

calculate distances between each three-dimensional point in thethree-dimensional point set and the reference plane to obtain a distanceset; and

determine the height of the stereo camera based on distances in thedistance set.

Optionally, the processor 503 is further configured to:

determine the reference plane equation ax+by+cz=0 based on the pitchangle θ and the tilt angle φ, such that a point (a, b, c) in a cameracoordinate system meets an angle conversion equation as follows:

${\lbrack y\rbrack = {{{\left\lbrack T^{- 1} \right\rbrack \lbrack x\rbrack}\mspace{14mu} {{wherein}\mspace{14mu}\lbrack x\rbrack}} = \begin{bmatrix}x_{r} \\y_{r} \\z_{r}\end{bmatrix}}},{\quad{{\lbrack y\rbrack = \begin{bmatrix}x_{c} \\y_{c} \\z_{c}\end{bmatrix}},{\lbrack T\rbrack = \begin{bmatrix}{\cos \; \phi} & {\cos \; {\theta sin}\; \phi} & {{- \sin}\; {\theta sin}\; \phi} \\{{- \sin}\; \phi} & {\cos \; {\theta cos\phi}} & {{- \sin}\; {\theta cos}\; \phi} \\0 & {\sin \; \theta} & {\cos \; \theta}\end{bmatrix}},}}$

[T⁻¹] is an inverse of matrix [T], (x_(c), y_(c), z_(c)) is a point inthe camera coordinate system, (x_(y), y_(y), z_(y)) is a point in theworld coordinate system corresponding to the point (x_(c), y_(c), z_(c))in the camera coordinate system, an origin of the world coordinatesystem coincides with an origin of the camera coordinate system, andcoordinate axes of the world coordinate system are correspondinglyparallel to coordinate axes of the world coordinate system.

Optionally, the processor 503 is further configured to:

calculate a distance Hi between an i^(th) three-dimensional point(x_(i), y_(i), z_(i)) by a first distance calculation equation based onthe three-dimensional point set and the reference plane equation,wherein the distance set includes the distance H_(i), 1≤i≤n, n being thetotal number of three-dimensional points in the three-dimensional pointset, and the first distance calculation equation is as follows:

$H_{i} = \frac{{{ax}_{i} + {by}_{i} + {cz}_{i}}}{\sqrt{a^{2} + b^{2} + c^{2}}}$

wherein the reference plane equation is ax+by+cz=0, a, b and c beingcoefficients of ax+by+cz=0.

Optionally, the processor 503 is further configured to:

determine a maximum distance in distances between each three-dimensionalpoint and the reference plane as the height of the stereo camera.

Optionally, the reference plane equation is ax+by+cz=0, a, b and c beingcoefficients of ax+by+cz=0; and the processor 503 is further configuredto:

count the distance set to establish a distance histogram by using apredefined width as a class width. Wherein a width in a horizontal axisof each rectangular column in the distance histogram indicates adistance range, and a length in a vertical axis of each rectangularcolumn in the distance histogram indicates the number of distanceswithin the distance range;

determine a middle point of width in the horizontal axis of therectangular column corresponding to a maximum distance range in thedistance histogram as a pre-selected height value H;

traverse each adjacent height value h around the pre-selected heightvalue H to determine a set of pre-selected plane by a predefined step,wherein each pre-selected plane in the set of pre-selected plane meetsthe equation ax+by+cz+d=0, d=−h; and each adjacent height value h meetshϵ(h−σ, h+σ), σ being a predefined value, and σ being greater than orequal to the predefined step, and less than the predefined width; thatis, f≤σ<g, wherein f being the predefined step, g being the predefinedwidth;

calculate distances between each three-dimensional point in thethree-dimensional point set and each pre-selected plane based on thethree-dimensional point set and the set of pre-selected plane;

for each pre-selected plane, determine a three-dimensional point, withthe distance between the three-dimensional point and the pre-selectedplane being greater than a predefined support threshold, as a supportpoint of the pre-selected plane;

determine a pre-selected plane having the most support points in the setof pre-selected plane as a target plane; and

determine an average value of distances between each support point inthe target plane and the reference plane as the height of the stereocamera.

Optionally, the processor 503 is further configured to:

calculate a distance H_(i)′ between the i^(th) three-dimensional point(x_(i), y_(i), z_(i)) and the first pre-selected plane by a seconddistance calculation equation based on the three-dimensional point setand the set of pre-selected plane, wherein 1≤i≤n, n being the totalnumber of three-dimensional points in the three-dimensional point set,and the second distance calculation equation is as follows:

$H_{i}^{\prime} = \frac{{{ax}_{i} + {by}_{i} + {cz}_{i} + d}}{\sqrt{a^{2} + b^{2} + c^{2}}}$

wherein the first pre-selected plane is a pre-selected plane in the setof pre-selected plane.

Optionally, the ground image includes a plurality of contiguous groundimages captured by the stereo camera; and the processor 503 is furtherconfigured to:

median filtering in time domain on the plurality of contiguous groundimages to obtain ground images after median filtering in time domain;

perform median filtering in space domain on each ground image aftermedian filtering in time domain to ground images after median filteringin space domain; and

determine depth information of each pixel on ground images after medianfiltering in space domain.

Optionally, the angle acquiring module 501 is an angle sensor, whereinthe angle sensor is in the stereo camera.

Optionally, the stereo camera according to examples of the presentdisclosure is a binocular stereo camera or a TOF stereo camera.

In summary, in the stereo camera according to examples of the presentdisclosure, the camera captures the ground image of a scenario where thestereo camera is deployed, and the processor determines thethree-dimensional point set which includes coordinate information ofeach three-dimensional point corresponding to each pixel on the groundimage, and determines the height of the stereo camera based on the angleinformation and the three-dimensional point set. In this way, the stereocamera may determine the height automatically thereof without definingan external reference structure, such that the operation complexity islowered, and the cost for determining the height is reduced.

With respect to the apparatus in above examples, details aboutperforming corresponding operations by different modules have beendescribed in the method examples, which are not given herein anyfurther.

Examples of the present disclosure provide a stereo camera, the stereocamera includes:

at least one processing component, wherein the processing component maybe a processor or a processing chip; and

a memory;

wherein the memory stores at least one program, configured to beexecuted by the at least one processing component, and configured to beexecuted by the at least one processing component to perform the methodfor acquiring height of stereo camera according to above examples.

The stereo camera further includes an angle acquiring module, forexample, an angle sensor, configured to acquire angle information of thestereo camera, wherein the angle information includes a pitch angle anda tilt angle; and a camera, configured to capture a ground image of ascenario where the stereo camera is deployed.

Examples of the present disclosure further provide a system foracquiring height of a stereo camera, the system includes: a remotecontrol apparatus and a stereo camera; wherein the remote controlapparatus is configured to remotely control the stereo camera; theremote control apparatus may be a smart phone, a computer, a wearabledevice, a server, or the like.

The stereo camera is the stereo camera as described in above examples ofthe present disclosure.

Examples of the present disclosure further provide system for acquiringheight of a stereo camera, the system includes: a remote controlapparatus and a stereo camera; wherein the remote control apparatus maybe a smart phone, a computer, a wearable device, a server, or the like.

The stereo camera is configured to: acquire angle information of thestereo camera (this process may be referenced to step 301 as describedabove), wherein the angle information includes a pitch angle and a tiltangle; capture a ground image of a scenario where the stereo camera isdeployed (this process may be referenced to step 302 as describedabove); and send the angle information and the ground image to theremote control apparatus.

The remote control apparatus is configured to: receive the angleinformation and the ground information; determine depth information ofeach pixel on the ground image (this process may be referenced to step303 as described above); establish a three-dimensional point set basedon depth information of each pixel on the ground image (this process maybe referenced to step 304 as described above), wherein thethree-dimensional point set includes coordinate information of eachthree-dimensional point corresponding to the each pixel on the groundimage; and determine height of the stereo camera based on the angleinformation and the three-dimensional point set (this process may bereferenced to step 305 as described above).

In summary, in the height acquisition system of a stereo cameraaccording to examples of the present disclosure, the ground image of thescenario where the stereo camera is deployed is captured, thethree-dimensional point set includes coordinate information of thethree-dimensional point corresponding to each pixel on the ground imageis determined based on depth information of each pixel on the groundimage, and the height of the stereo camera is determined based on theangle information and the three-dimensional point set. In this way, thestereo camera may automatically determine the height without adefinition for an external reference structure, thereof lowing theoperation complexity, and reducing cost for determining the height. Inaddition, in examples of the present disclosure, as long as an imagecaptured by the stereo camera include a ground image, the stereo cameramay use the ground image as a reference to determine the height thereof.The way of determining the external parameters is concise, and has highrobustness.

Further, since the external reference structure is unnecessary duringdetermination of the height of the stereo camera, the operatingpersonnel may not handle the on-site environment. Therefore, the staffdoes not need to handle the environment, and no need to be in thevicinity of the stereo camera, thereby the stereo camera could becontrolled remotely.

In examples, the present disclosure further provides a non-transitorycomputer-readable storage medium, which stores code instructions;wherein the code instructions are executed by a processor to perform theheight acquisition methods of a stereo camera as described in the aboveexamples. For example, the non-volatile computer-readable storage mediummay be a read-only memory (ROM), a random access memory (RAM), a compactdisc ROM (CD-ROM), a magnetic tape, a floppy disk, an optical datastorage device or the like.

Other examples of the present disclosure will be apparent to thoseskilled in the art from consideration of the specification and practiceof the present disclosure. This application is intended to cover anyvariations, uses, or adaptations of the present disclosure following thegeneral principles thereof and including common knowledge or commonlyused technical measures which are not disclosed herein. Thespecification and examples are to be considered as exemplary only, witha true scope and spirit of the present disclosure is indicated by thefollowing claims.

The technical solutions according to examples of the present disclosuremay achieve the following beneficial effects:

In summary, examples of the present disclosure provide a stereo camera,method and system for acquiring height of stereo camera thereof, theground image of the scenario where the stereo camera is deployed iscaptured, then the three-dimensional point set recording coordinateinformation of each three-dimensional point corresponding to each pixelon the ground image is determined based on depth information of eachpixel on the ground image, and the height of the stereo camera isdetermined based on the angle information and the three-dimensionalpoint set. In this way, the stereo camera automatically determines theheight thereof without defining an external reference structure, suchthat the operation complexity is lowered, and the cost for determiningthe height is reduced.

Other examples of the present application will be readily apparent tothose skilled in the technical field, the application is intended tocover any variations, uses, or adaptations of the application, which arein accordance with the general principles of the application and includecommon general knowledge or common technical means in the art that arenot disclosed herein. The specification and examples are to be regardedas illustrative only, the scope and principle of the application ispointed out by the claims.

It will be appreciated that the present disclosure is not limited to theexact construction that has been described above and illustrated in theaccompanying drawings, and that various modifications and changes can bemade without departing from the scope thereof. It is intended that thescope of the present disclosure only be limited by the appended claims.

What is claimed is:
 1. A method for acquiring a height of a stereocamera, applied to the stereo camera, the method comprising: acquiringangle information of a stereo camera, wherein the angle informationincludes a pitch angle and a tilt angle; capturing a ground image of ascenario where the stereo camera is deployed; determining depthinformation of each pixel on the ground image; establishing athree-dimensional point set based on the depth information of each pixelon the ground image, wherein the three-dimensional point set includescoordinate information of each three-dimensional point corresponding toeach pixel of the ground image; and determining the height of the stereocamera based on the angle information and the three-dimensional pointset.
 2. The method according to claim 1, wherein the determining theheight of the stereo camera based on the angle information and thethree-dimensional point set, comprises: determining, based on the pitchangle and the tilt angle, a reference plane equation corresponding to areference plane, wherein the reference plane is parallel to a horizonplane in a world coordinate system, and a center point of a lens of thestereo camera is within the reference plane; calculating distancesbetween each three-dimensional point in the three-dimensional point setand the reference plane to obtain a distance set; and determining theheight of the stereo camera based on the distances in the distance set.3. The method according to claim 2, wherein the determining, based onthe pitch angle and the tilt angle, a reference plane equationcorresponding to a reference plane, comprises: determining the referenceplane equation ax+by+cz=0 based on the pitch angle θ and the tilt angleφ, such that a point (a, b, c) in a camera coordinate system meets anangle conversion equation:${{\lbrack y\rbrack = {\left\lbrack T^{- 1} \right\rbrack \lbrack x\rbrack}};{{{wherein}\mspace{14mu}\lbrack x\rbrack} = \begin{bmatrix}x_{r} \\y_{r} \\z_{r}\end{bmatrix}}},{\quad{{\lbrack y\rbrack = \begin{bmatrix}x_{c} \\y_{c} \\z_{c}\end{bmatrix}},{\lbrack T\rbrack = \begin{bmatrix}{\cos \; \phi} & {\cos \; {\theta sin}\; \phi} & {{- \sin}\; {\theta sin}\; \phi} \\{{- \sin}\; \phi} & {\cos \; {\theta cos\phi}} & {{- \sin}\; {\theta cos}\; \phi} \\0 & {\sin \; \theta} & {\cos \; \theta}\end{bmatrix}},}}$ [T⁻¹] is an inverse of matrix [T], (x_(c), y_(c),z_(c)) is a point in the camera coordinate system, and (x_(y), y_(y),z_(y)) is a point in the world coordinate system corresponding to thepoint (x_(c), y_(c), z_(c)) in the camera coordinate system, wherein anorigin of the world coordinate system coincides with an origin of thecamera coordinate system, and coordinate axes of the world coordinatesystem are correspondingly parallel to coordinate axes of the worldcoordinate system.
 4. The method according to claim 2, wherein thecalculating distances between each three-dimensional point in thethree-dimensional point set and the reference plane to obtain a distanceset, comprises: calculating a distance H_(i) between an i^(th)three-dimensional point (x_(i), y_(i), z_(i)) and the reference plane byusing a first distance calculation equation based on thethree-dimensional point set and the reference plane equation, whereinthe distance set comprises the distance H_(i), 1≤i≤n, n being the totalnumber of three-dimensional points in the three-dimensional point set,and the first distance calculation equation is:${H_{i} = \frac{{{ax}_{i} + {by}_{i} + {cz}_{i}}}{\sqrt{a^{2} + b^{2} + c^{2}}}};$wherein the reference plane equation is ax+by+cz=0, a, b and c beingcoefficients of ax+by+cz=0.
 5. The method according to claim 2, whereinthe determining the height of the stereo camera based on the distancesin the distance set, comprises: combining the distances in the distanceset to obtain a target distance set, wherein distances in the targetdistance set are different from each other, each distance corresponds anumber of times, and the number of times indicates a times count ofoccurrences of a corresponding distance in the distance set; anddetermining a distance corresponding a maximum number of times in thetarget distance set as the height of the stereo camera.
 6. The methodaccording to claim 2, wherein the reference plane equation isax+by+cz=0, a, b and c being coefficients of ax+by+cz=0; and wherein thedetermining the height of the stereo camera based on the distances inthe distance set, comprises: forming, by a predefined width as a classwidth, a distance histogram according the distance set, wherein herein awidth in a horizontal axis of each rectangular column in the distancehistogram indicates a distance range, and a length in a vertical axis ofeach rectangular column in the distance histogram indicates the numberof distances within the distance range; determining a middle point ofwidth in the horizontal axis of a rectangular column having a maximumdistance range in the distance histogram as a pre-selected height valueH; traversing, by a predefined step, each adjacent height value h aroundthe pre-selected height value H to obtain a set of pre-selected plane,wherein each pre-selected plane in the set of pre-selected plane meetsthe equation ax+by+cz+d=0, d=−h; and each adjacent height value h meetshϵ(h−σ, h+σ), σ being a predefined value, and σ being greater than orequal to the predefined step, and less than the predefined width;calculating distances between each three-dimensional point and eachpre-selected plane based on the three-dimensional point set and the setof pre-selected plane; determining a three-dimensional point with thedistance to the pre-selected plane being greater than a predefinedsupport threshold as a support point of the pre-selected plane;determining a pre-selected plane having the most support points in thepre-selected planes set as a target plane; and determining an averagevalue of distances between each support point in the target plane andthe reference plane as the height of the stereo camera.
 7. The methodaccording to claim 6, wherein the calculating distances between eachthree-dimensional point and each pre-selected plane based on thethree-dimensional point set and the set of pre-selected plane,comprises: calculating a distance H_(i)′ between the i^(th)three-dimensional point (x_(i), y_(i), z_(i)) and the first pre-selectedplane by a second distance calculation equation based on thethree-dimensional point set and the set of pre-selected plane, wherein1≤i≤n, n being the total number of three-dimensional points in thethree-dimensional point set, and the second distance calculationequation being:$H_{i}^{\prime} = \frac{{{ax}_{i} + {by}_{i} + {cz}_{i} + d}}{\sqrt{a^{2} + b^{2} + c^{2}}}$wherein the first pre-selected plane is a pre-selected plane in the setof pre-selected plane.
 8. The method according to claim 1, wherein theground image includes a plurality of contiguous ground images capturedby the stereo camera; and wherein the determining depth information ofeach pixel on the ground image, comprises: performing median filteringin time domain on the plurality of contiguous ground images to obtain aplurality of ground images after median filtering in time domain;performing median filtering in space domain on the plurality of groundimages after median filtering in time domain to obtain a plurality ofground images after median filtering in space domain; and determiningdepth information of each pixel on the ground images after medianfiltering in space domain.
 9. A stereo camera, comprising: at least oneprocessing component; and a memory; wherein the memory storesinstructions that when executed by the at least one processingcomponent, cause the at least one processing component to performoperations comprising: acquiring angle information of a stereo camera,wherein the angle information includes a pitch angle and a tilt angle,capturing a ground image of a scenario where the stereo camera isdeployed, determining depth information of each pixel on the groundimage, establishing a three-dimensional point set based on depthinformation of each pixel on the ground image, wherein thethree-dimensional point set includes coordinate information of eachthree-dimensional point corresponding to each pixel of the ground image;and determining the height of the stereo camera based on the angleinformation and the three-dimensional point set.
 10. The stereo cameraaccording to claim 9, wherein the determining the height of the stereocamera based on the angle information and the three-dimensional pointset, comprises: determining, based on the pitch angle and the tiltangle, a reference plane equation corresponding to a reference plane,wherein the reference plane is parallel to a horizon plane in a worldcoordinate system, and a center point of a lens of the stereo camera iswithin the reference plane; calculating distances between eachthree-dimensional point in the three-dimensional point set and thereference plane to obtain a distance set; and determining the height ofthe stereo camera based on the distances in the distance set.
 11. Thestereo camera according to claim 10, wherein the determining, based onthe pitch angle and the tilt angle, a reference plane equationcorresponding to a reference plane, comprises: determining the referenceplane equation ax+by+cz=0 based on the pitch angle θ and the tilt angleφ, such that a point (a, b, c) in a camera coordinate system meets anangle conversion equation:${{\lbrack y\rbrack = {\left\lbrack T^{- 1} \right\rbrack \lbrack x\rbrack}};{{{wherein}\mspace{14mu}\lbrack x\rbrack} = \begin{bmatrix}x_{r} \\y_{r} \\z_{r}\end{bmatrix}}},{\quad{{\lbrack y\rbrack = \begin{bmatrix}x_{c} \\y_{c} \\z_{c}\end{bmatrix}},{\lbrack T\rbrack = \begin{bmatrix}{\cos \; \phi} & {\cos \; {\theta sin}\; \phi} & {{- \sin}\; {\theta sin}\; \phi} \\{{- \sin}\; \phi} & {\cos \; {\theta cos\phi}} & {{- \sin}\; {\theta cos}\; \phi} \\0 & {\sin \; \theta} & {\cos \; \theta}\end{bmatrix}},}}$ [T⁻¹] is an inverse of matrix [T], (x_(c), y_(c),z_(c)) is a point in the camera coordinate system, and (x_(y), y_(y),z_(y)) is a point in the world coordinate system corresponding to thepoint (x_(c), y_(c), z_(c)) in the camera coordinate system, wherein anorigin of the world coordinate system coincides with an origin of thecamera coordinate system, and coordinate axes of the world coordinatesystem are correspondingly parallel to coordinate axes of the worldcoordinate system.
 12. The stereo camera according to claim 10, whereinthe calculating distances between each three-dimensional point in thethree-dimensional point set and the reference plane to obtain a distanceset, comprises: calculating a distance H_(i) between an i^(th)three-dimensional point (x_(i), y_(i), z_(i)) and the reference plane byusing a first distance calculation equation based on thethree-dimensional point set and the reference plane equation, whereinthe distance set comprises the distance H_(i), 1≤i≤n, n being the totalnumber of three-dimensional points in the three-dimensional point set,and the first distance calculation equation is:${H_{i} = \frac{{{ax}_{i} + {by}_{i} + {cz}_{i}}}{\sqrt{a^{2} + b^{2} + c^{2}}}};$wherein the reference plane equation is ax+by+cz=0, a, b and c beingcoefficients of ax+by+cz=0.
 13. The stereo camera according to claim 10,wherein the determining the height of the stereo camera based on thedistances in the distance set, comprises: combining the distances in thedistance set to obtain a target distance set, wherein distances in thetarget distance set are different from each other, each distancecorresponds a number of times, and the number of times indicates a timescount of occurrences of a corresponding distance in the distance set;and determining a distance corresponding a maximum number of times inthe target distance set as the height of the stereo camera.
 14. Thestereo camera according to claim 10, wherein the reference planeequation is ax+by+cz=0, a, b and c being coefficients of ax+by+cz=0; andwherein the determining the height of the stereo camera based on thedistances in the distance set, comprises: forming, by a predefined widthas a class width, a distance histogram according the distance set,wherein herein a width in a horizontal axis of each rectangular columnin the distance histogram indicates a distance range, and a length in avertical axis of each rectangular column in the distance histogramindicates the number of distances within the distance range; determininga middle point of width in the horizontal axis of a rectangular columnhaving a maximum distance range in the distance histogram as apre-selected height value H; traversing, by a predefined step, eachadjacent height value h around the pre-selected height value H to obtaina set of pre-selected plane, wherein each pre-selected plane in the setof pre-selected plane meets the equation ax+by+cz+d=0, d=−h; and eachadjacent height value h meets hϵ(h−σ, h+σ), σ being a predefined value,and σ being greater than or equal to the predefined step, and less thanthe predefined width; calculating distances between eachthree-dimensional point and each pre-selected plane based on thethree-dimensional point set and the set of pre-selected plane;determining a three-dimensional point with the distance to thepre-selected plane being greater than a predefined support threshold asa support point of the pre-selected plane; determining a pre-selectedplane having the most support points in the pre-selected planes set as atarget plane; and determining an average value of distances between eachsupport point in the target plane and the reference plane as the heightof the stereo camera.
 15. A height acquisition system, comprising: aremote control apparatus and a stereo camera; wherein the stereo camerais configured to: acquire angle information of the stereo camera,wherein the angle information includes a pitch angle and a tilt angle;capture a ground image of a scenario where the stereo camera isdeployed; and send the angle information and the ground image to theremote control apparatus; and wherein the remote control apparatus isconfigured to: receive the angle information and the ground image;determine depth information of each pixel on the ground image; establisha three-dimensional point set based on depth information of each pixelon the ground image, wherein the three-dimensional point set includescoordinate information of each three-dimensional point corresponding toeach pixel on the ground image; and determine the height of the stereocamera based on the angle information and the three-dimensional pointset.
 16. The height acquisition system according to claim 15, whereinwhen determining the height of the stereo camera based on the angleinformation and the three-dimensional point set, the remote controlapparatus is configured to: determine, based on the pitch angle and thetilt angle, a reference plane equation corresponding to a referenceplane, wherein the reference plane is parallel to a horizon plane in aworld coordinate system, and a center point of a lens of the stereocamera is within the reference plane; calculate distances between eachthree-dimensional point in the three-dimensional point set and thereference plane to obtain a distance set; and determine the height ofthe stereo camera based on the distances in the distance set.
 17. Theheight acquisition system according to claim 16, wherein whendetermining, based on the pitch angle and the tilt angle, a referenceplane equation corresponding to a reference plane, the remote controlapparatus is configured to: determine the reference plane equationax+by+cz=0 based on the pitch angle θ and the tilt angle φ, such that apoint (a, b, c) in a camera coordinate system meets an angle conversionequation:${{\lbrack y\rbrack = {\left\lbrack T^{- 1} \right\rbrack \lbrack x\rbrack}};{{{wherein}\mspace{14mu}\lbrack x\rbrack} = \begin{bmatrix}x_{r} \\y_{r} \\z_{r}\end{bmatrix}}},{\quad{{\lbrack y\rbrack = \begin{bmatrix}x_{c} \\y_{c} \\z_{c}\end{bmatrix}},{\lbrack T\rbrack = \begin{bmatrix}{\cos \; \phi} & {\cos \; {\theta sin}\; \phi} & {{- \sin}\; {\theta sin}\; \phi} \\{{- \sin}\; \phi} & {\cos \; {\theta cos\phi}} & {{- \sin}\; {\theta cos}\; \phi} \\0 & {\sin \; \theta} & {\cos \; \theta}\end{bmatrix}},}}$ [T⁻¹] is an inverse of matrix [T], (x_(c), y_(c),z_(c)) is a point in the camera coordinate system, and (x_(y), y_(y),z_(y)) is a point in the world coordinate system corresponding to thepoint (x_(c), y_(c), z_(c)) in the camera coordinate system, wherein anorigin of the world coordinate system coincides with an origin of thecamera coordinate system, and coordinate axes of the world coordinatesystem are correspondingly parallel to coordinate axes of the worldcoordinate system.
 18. The height acquisition system according to claim16, wherein when calculating distances between each three-dimensionalpoint in the three-dimensional point set and the reference plane toobtain a distance set, the remote control apparatus is configured to:calculate a distance H_(i) between an i^(th) three-dimensional point(x_(i), y_(i), z_(i)) and the reference plane by using a first distancecalculation equation based on the three-dimensional point set and thereference plane equation, wherein the distance set comprises thedistance H_(i), 1≤i≤n, n being the total number of three-dimensionalpoints in the three-dimensional point set, and the first distancecalculation equation is:${H_{i} = \frac{{{ax}_{i} + {by}_{i} + {cz}_{i}}}{\sqrt{a^{2} + b^{2} + c^{2}}}};$wherein the reference plane equation is ax+by+cz=0, a, b and c beingcoefficients of ax+by+cz=0.
 19. The height acquisition system accordingto claim 16, wherein when determining the height of the stereo camerabased on the distances in the distance set, the remote control apparatusis configured to: combine the distances in the distance set to obtain atarget distance set, wherein distances in the target distance set aredifferent from each other, each distance corresponds a number of times,and the number of times indicates a times count of occurrences of acorresponding distance in the distance set; and determine a distancecorresponding a maximum number of times in the target distance set asthe height of the stereo camera.
 20. The height acquisition systemaccording to claim 16, wherein the reference plane equation isax+by+cz=0, a, b and c being coefficients of ax+by+cz=0; and whereinwhen determining the height of the stereo camera based on the distancesin the distance set, the remote control apparatus is configured to:form, by a predefined width as a class width, a distance histogramaccording the distance set, wherein herein a width in a horizontal axisof each rectangular column in the distance histogram indicates adistance range, and a length in a vertical axis of each rectangularcolumn in the distance histogram indicates the number of distanceswithin the distance range; determine a middle point of width in thehorizontal axis of a rectangular column having a maximum distance rangein the distance histogram as a pre-selected height value H; traverse, bya predefined step, each adjacent height value h around the pre-selectedheight value H to obtain a set of pre-selected plane, wherein eachpre-selected plane in the set of pre-selected plane meets the equationax+by+cz+d=0, d=−h; and each adjacent height value h meets hϵ(h−σ, h+σ),σ being a predefined value, and σ being greater than or equal to thepredefined step, and less than the predefined width; calculate distancesbetween each three-dimensional point and each pre-selected plane basedon the three-dimensional point set and the set of pre-selected plane;determine a three-dimensional point with the distance to thepre-selected plane being greater than a predefined support threshold asa support point of the pre-selected plane; determine a pre-selectedplane having the most support points in the pre-selected planes set as atarget plane; and determine an average value of distances between eachsupport point in the target plane and the reference plane as the heightof the stereo camera.